Among them is Prarameswaran Subramaniam, who has been on hunger strike since April 7th.

The 28-year-old lost several members of his family in the conflict and has vowed not to eat until a ceasefire is agreed, although he did accept some water.

Gordon Brown has sent Des Browne to the United Nations in New York to push for a ceasefire, but it is unlikely to be forthcoming as China and Russia regard the civil war as a purely internal issue for Colombo.

The Sri Lankan military - and most analysts - are convinced the Tamil Tigers are now on their last legs, and are desperate to push ahead with their campaign.

But tens of thousands of civilians are also caught up in the fighting between the two groups.

On Monday, thousands of Tamil demonstrators broke through police lines around Westminster.

The Tamils represent a distinct ethnic group who want a separate state in the north and east of Sri Lanka.